Network Working Group M. Bagnulo
Request for Comments: 5535 UC3M
Category: Standards Track June 2009
Hash-Based Addresses (HBA)
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
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Abstract
This memo describes a mechanism to provide a secure binding between
the multiple addresses with different prefixes available to a host
within a multihomed site. This mechanism employs either
Cryptographically Generated Addresses (CGAs) or a new variant of the
same theme that uses the same format in the addresses. The main idea
in the new variant is that information about the multiple prefixes is
included within the addresses themselves. This is achieved by
generating the interface identifiers of the addresses of a host as
Bagnulo Standards Track [Page 1]RFC 5535 HBA June 2009
hashes of the available prefixes and a random number. Then, the
multiple addresses are generated by prepending the different prefixes
to the generated interface identifiers. The result is a set of
addresses, called Hash-Based Addresses (HBAs), that are inherently
bound to each other.
Table of Contents
1. Introduction ....................................................3
2. Terminology .....................................................4
3. Overview ........................................................4
3.1. Threat Model ...............................................4
3.2. Overview ...................................................4
3.3. Motivations for the HBA Design .............................5
4. Cryptographic Generated Addresses (CGAs) Compatibility
Considerations ..................................................6
5. Multi-Prefix Extension for CGA ..................................8
6. HBA-Set Generation ..............................................9
7. HBA Verification ...............................................11
7.1. Verification That a Particular HBA Address
Corresponds to a Given CGA Parameter Data Structure .......11
7.2. Verification That a Particular HBA Address Belongs to the
HBA Set Associated with a Given CGA Parameter Data
Structure .................................................11
8. Example of HBA Application in a Multihoming Scenario ...........13
8.1. Dynamic Address Set Support ...............................16
9. DNS Considerations .............................................17
10. IANA Considerations ...........................................18
11. Security Considerations .......................................18
11.1. Security Considerations When Using HBAs in the
Shim6 Protocol ...........................................20
11.2. Privacy Considerations ...................................22
11.3. SHA-1 Dependency Considerations ..........................22
11.4. DoS Attack Considerations ................................22
12. Contributors ..................................................23
13. Acknowledgments ...............................................23